Arrange in order of highest to lowest correlation of IQ among various types of children:
(A) Identical twins reared together
(B) Identical twins reared apart
(C) Fraternal twins reared together
(D) Siblings reared apart
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → (A), (B), (C), (D)
Studies of twins and siblings show the role of heredity in intelligence: the closer the genetic link and the more similar the environment, the higher the correlation of IQ.
(A) Identical twins reared together — highest, almost 0.90. They share all their genes and the same home.
(B) Identical twins reared apart — next, 0.72. The genes are the same, but different environments lower the correlation.
(C) Fraternal twins reared together — next, almost 0.60. They share a home but only part of their genes.
(D) Siblings reared apart — lowest, about 0.25. Only part of the genes are shared, and the environments differ.
NCERT (2025-26): “Intelligence: Interplay of Nature and Nurture … The intelligence of identical twins reared together correlate almost 0.90. Twins separated early in childhood also show considerable similarity in their intellectual, personality and behavioural characteristics. The intelligence of identical twins reared in different environments correlate 0.72, those of fraternal twins reared together correlate almost 0.60, and those of brothers and sisters reared together correlate about 0.50, while siblings reared apart correlate about 0.25.…” |